Container for electrical apparatus



May 14, 1929.

al v A F. wlLD 1,712,538

CONTAINER FOR ELECTRICAL APPARATUS Filed sept. 29, 1926 Patented May 14, 1929.

UNITED STATES PATENT OFFICE.

FRIEDRICH WILD, OF BADEN, SWITZERLAND, ASSIGNOR TO AKTIENGESELLSCHAFT BROWN BOVERI & CIE., OF BADEN, SWITZERLAND, A JOINT-STOCK COMPANY OF SWITZERLAND.

CONTAINER FOR ELECTRICAL APPARATUS.

Application filed September 29, 1926, Serial No. 138,500, and in Germany October 28, 1925.

rlhis invention relates to construction of containers or tanks for the housing of electrical apparatus, such as transformers, circuit breakers, and the like, which is kept immersed in oil for purposes of protection, insulation and the like.

The general object of the invention is the provision of a container construction which will afford safeguard against rupturing of the tank from abnormal internal fluid pressures Which may be generated therein incident to heating of the contained oil or vapour, as by short circuits, arcing, or operation of the enclosed apparatus.

Another object is the provision of a construction for a container of the sort specified which Will afford such safeguard against the effects of internal pressures While permitting the tank to be kept full of oil.

Other and further objects will be pointed out or indicated hereinafter or will be apparent to one skilled inthe art upon an understanding of the invention or its employment in practice.

In the drawing forming a part of this specification I illustrate one form of structure in which the invention may be embodied, but it is to be understood that this is presented for purpose of illustration only and is not to be given any interpretation having the effect of limiting the claims short of the true and most comprehensive scope of the invention in the art.

In the drawing,

Fig. 1 is a sectional elevational view of a 'transformer casing, same having parts shownr in diagrammatic fashion and being taken across the longitudinal dimension of the tank;

Fig. 2 is a sectional elevation on the longitudinal dimension of the tank; and

Fig. 3 is a cross-sectional view looking upwardly on approximately line 8-3 of Fig. 2.

The nature of the invention Will be ascertained immediately from the illustrative embodiment. In the construction illustrated let it be understood that the reference numeral 10 designates a tank in which the electrical apparatus, represented by the transformer 11, is housed. This tank has a closed cover 12 closing it at the top, and also supports the brackets 14 which carry an expansion tank 15 at an elevation above the cover 12. The tank 10 is filled with oil, and the expansion tank 15 is to contain an excess quantity of oil Which is supplied by gravity to the tank 1() by way of pipe 16, to make up any losses from tank 10. Tank 10 is provided with a relief valve 13 adapted to operate upon predetermined pressure Within the tank to permit the venting of gas-es from the tank. IVithin tank 1() are provided relief chambers 17 which are air compartments segregated from the oil in the tank by thin Walls of. deformable matcrial, such as sheet metal. These compartments contain air and are in communication with the external atmosphere by Way of vent pipes 18 which open under the caps 19 at an elevation above the maximum oil level of the tank 15. The Walls of compartments 17 are made of a material which Will permit their collapsing under a predetermined pressure imposed on them through the surrounding oil, and the vent pipes 18 afford paths for the expulsion of air from the compartments 17 incident to their collapsing.

By virtue of this constructiontherefore, in the event a pressure is generated in the tank 10 in excess of the maximum Which the compartments 17 are designed to Withstand, the Walls of the compartments will be collapsed, thereby affording space Within the tank to relieve the pressure, the air contained Within the compartments being expelled through the vent pipes. The imm-ediate relief of pressure thus afforded by the collapse of the relief compartments will safeguard the tank against being ruptured by the sudden rise of pressure in it, giving the relief valve 13 time to open and permit the venting from the tank of the gases generated therein, and which constitute the source of the abnormal pressure.

hat I claim is:

1. In electrical apparatus, a relatively rigid closed tank adapted to be completely filled With fluidv under low hydro-static pressure, means for maintaining the hydrostatic pressure, a pressure relief air chamber open on one side and sealed at the open side against said tank, said chamber being formed from relatively fragile material collapsible under abnormal pressure conditions in said tank, and means permitting escape of air to the atmosphere from said chamber upon collapse thereof.

n above said pressure maintaining means to permit escape of air from said chamber upon collapse thereof.

3. In electrical apparat-us, a relatively rigid closed tank adapted to be completely filled with fluid under low hydro-static pressure, means for maintaining the hydrostatic pressure, a pressure relief chamber open on one side and sealed at the open side against said tank, said chamber being formed from relatively fragile metal collapsible under abnormal pressure conditions in said tank, means for sealing said chamber against said tank, and means permitting escape of air to the atmosphere from said chamber upon collapse thereof.

4. In electrical apparatus, a relatively rigid tank adapted to be completely filled with fluid under loW hydro-static pressure, means for maintaining the hydro-static pressure, a pressure relief chamber open on one side and sealed at the open side against said tank, said chamber being formed of metal collapsible under abnormal pressure conditions in said tank, tubular vents extending above said pressure maintaining means to permit escape of air from said chamber upon collapse thereof, and a valve means joined to said tank to permit escape of air therefrom after collapse of said chamber.

In testimony whereof I have hereunto subscribed my name at Baden, Switzerland, on the 9th day of September, A. D. 1926.

FRIEDR. \VILI). 

